Waterproof locking-type electric plug and receptacle coupling

ABSTRACT

Electric coupling comprising plug and receptacle parts having contact pins and cooperable contactor sockets carried respectively by plug and receptacle bodies of insulating material. The bodies include portions which have a telescoping fit and which have, on contacting or mating cylindrical inner and outer surfaces, a cooperable annular detent bead and detent groove by which the bodies are releasably held assembled. At such cylindrical surfaces a sealing O-ring is provided on one body and a sharp sealing shoulder on the other body, adapted to bite into the O-ring to effect a watertight seal. The biting engagement is characterized by axial force as distinguished from radial force. The contactor sockets are of a greater width than the contact prongs whereby the latter can move edgewise in the sockets, enabling the plug and receptacle bodies to be separated by employing a relative angular movement which forces the detent bead out of the cooperable annular detent groove. A flattened configuration on one body, with or without imprinted words, indicates the direction of angular separating force which is required to separate the bodies. A plurality of arcuate sealing wedges are forced around the electric cords at the inside of the collars of the bodies, said wedges being held in place by snap caps to effect a securement of the electric cords as well as to seal the same where they enter the bodies.

United States Patent [72] Inventor Arthur M. Hirrb 135 Southwood Road, Fairfield, Conn. 06430 [21 Appl. No. 853,898 [22] Filed Aug. 28, 1969 [45] Patented Aug. 24, 1971 [54] WATERPROOF LOCKING-TYPE ELECTRIC PLUG AND RECEPTACLE COUPLING 9 Claims, 10 Drawing Figs.

[52] US. Cl v. 339/61 R, 339/94 R, 339/103 C [51 Int. Cl H0lr 13/08 [50] Field ofSear-ch 339/59-61, 94, 103, 36

[56] References Cited UNITED STATES PATENTS 2,717,367 9/1955 Puemer 339/185 2,941,178 6/1960 Hubbell et al. 339/92 2,956,107 10/1960 Monashkin 174/71 3,124,405 3/1964 Massa 339/60 3,188,380 6/1965 Lorenz 174/75 3,199,060 8/1965 Marasco 339/60 FOREIGN PATENTS 1,127,425 4/1962 Germany 339/94 Primary Examiner-loseph H. McGlynn Attorney-H. Gibner Lehmann ABSTRACT: Electric coupling comprising plug and receptacle parts having contact pins and cooperable contactor sockets carried respectively by plug and receptacle bodies of insulating material. The bodies include portions which have a telescoping fit and which have, on contacting or mating cylindrical inner and outer surfaces, a cooperable annular detent bead and detent groove by which the bodies are releasably held assembled. At such cylindrical surfaces a sealing O-ring is provided on one body and a sharp sealing shoulder on the other body, adapted to bite into the O-ring to effect a watertight seal. The biting engagement is characterized by axial force as distinguished from radial force. The contactor sockets are of a greater width than the contact prongs whereby the latter can move edgewise in the sockets, enabling the plug and receptacle bodies to be separated by employing a relative angular movement which forces the detent bead out of the cooperable annular detent groove. A flattened configuration on one body, with or without imprinted words, indicates the direction of angular separating force which is required to separate the bodies. A plurality of arcuate sealing wedges are forced around the electric cords at the inside of the collars of the bodies, said wedges being held in place by snap caps to effect a securement of the electric cords as well as to seal the same where they enter the bodies.

WATERPROOF LOCKING-TYPE ELECTRIC PLUG AND RECEPTACLE COUPLING BACKGROUND This invention relates to electric couplings comprising plug and receptacle devices, and more particularly to devices of this type wherein the plug and receptacle bodies are securely releasably held together and have sealing means providing for waterproofing.

In the past various lockingand sealing-type plug and receptacle devices have been proposed and produced, involving locking prongs, radial-acting sealing or O-rings and the like. While these devices have served useful functions, they suffered a number of drawbacks and disadvantages. The locking prong construction was costly and not especially easy to operate. The radial-acting sealing or O-rings were not always effective and sometimes caused considerably binding, making for difiiculty in separating the plug and receptacle bodies, or properly assembling the same. Relative sliding movements that occurred between the cooperable plug and receptacle parts seemed to present no problems when the parts were new or first put into use, but caused difficulty later when the parts became soiled or dirty. In consequence, devices which in the new condition worked satisfactorily, developed faults and problems after experiencing a period of use.

SUMMARY The above drawbacks and disadvantages of prior lockingand sealing-type electric plug and receptacle couplings are obviated by the present invention, one object being to provide an 1 improved device of this type which has an effective detent or retention means and waterproofing means while at the same time being of especially simple construction whereby the production cost can be held to a low, attractive figure. This is accomplished by the provision of plug and receptacle bodies which have cylindrical telescoping portions of yieldable plastic substance provided one with an annular detent bead and the other with an annular cooperable detent groove, both being of relatively small depth or height by which there is had an easy snap action at the same time that they provide an effective detent to hold the bodies in assembled condition. To separate the bodies a relative angular or .breaking force is applied, to cause one body to cant or tilt with respect to the other, resulting in displacement of the detent bead from its cooperable groove whereby the bodies readily separate. The contactor sockets for the prongs are made with sufficient clearance to enable such relative angular movement to be effected. In conjunction with the telescopic detent portions there is provided a sealing O-ring engageable with a sharp shoulder at the end of one cylindrical portion to effect a seal by forces which are mainly axial as distinguished from radial. The axial-force type seal involving the O-ring is not susceptible to binding, and accordingly the assembly and separation of the plug and receptacle bodies cannot be adversely affected by the seal.

Other objects and advantages of the invention reside in the provision of an improved electric plug and receptacle device as above set forth, wherein improved and simplified means effect a sealing of the electric cords at the points of entrance to the bodies; wherein the assembly and retention of the bodies is accomplished by a simple straight-line movement in axial directions; and wherein replacement of the sealing O-ring can be easily and quickly effected if this should be required after a period of use. Still other features and advantages will hereinafier appear.

In the drawings:

FIG. 1 is a side elevational view of a plug and receptacle device, in assembled condition, constituting one embodiment of the invention.

FIG. 2 is an exploded view partly in side elevation and partly in section, of the plug and receptacle device in the separated condition.

FIG. 3 is an end elevational view of the receptacle portion of the device.

FIG. 4 is a transverse section taken on the line 4-4 of FIG. 1.

FIG. 5 is an enlarged fragmentary sectional view through a cap and collar portion of the device, taken on the line 5-5 of FIG. 4.

FIG. 6 is a sectional view of one of the sealing wedges employed to secure and seal an electric cord of the device.

FIG. 7 is an outside elevational view of the wedge of FIG. 6.

FIG. 8 is a fragmentary view partly in section and partly in side elevation, illustrating another form of receptacle made in accordance with the invention.

FIG. 9 is an axial sectional view of a snap cover for use with the receptacle of the invention, to close or seal the same when it is not being used.

FIG. 10 is a disassembled side elevational view of a plug and receptacle device illustrating yet another embodiment of the invention.

Referring first to the embodiment of FIGS. 1-7, the plug and receptacle device of the invention shown therein comprises a plug part comprising a body 20 and a receptacle part comprising a body 22, the latter having recesses 24 containing contactor sockets 25 for receiving contact prongs 26 carried by the body 20. The bodies 20, 22 have reference axes x, x, and are preferably constructed with integral collars 28, 30 respectively through which electric cords 32, 34 extend.

The plug and receptacle bodies 20, 22 are constituted of molded plastic of resilient or yieldable characteristic whereby wall sections thereof can readily bend or yield without becoming broken, said sections returning to the original molded shape after removal of the deforming force.

In accordance with the present invention, the plug and receptacle bodies 20, 22 have novel annular telescoping retainer portions 36, 38 respectively, the latter portion slidably fitting within the portion 36 and said portions being provided with cooperable releasable detent means of especially simple construction, which clearly hold the bodies in assembled relation yet permit them to be easily and quickly separated when this should be desired.

In effecting the detent action, the telescopic portions 36, 38 are provided with cooperable shoulder formations comprising annular tongue-and-groove or bead-and-groove shapes. As shown, the portion 38 has an annular bead 40 and the portion 36 has an annular groove 42 adapted to receive the bead 40 with a snap action. The head 40 is closely adjacent the front end surface 44 of the receptacle body 22, and the groove 42 is preferably closely adjacent the inner transverse wall 46 of the plug body 20. With the above construction and considering the resilient nature of the molded plastic constituting the bodies, it is possible to snap the portion 38 of the receptacle body 22 easily and quickly into the portion 36 of the plug body 20 by arranging the relative diameters of the portions properly. It will be understood that the detent bead 40 and the cooperable groove 42 each have a small height and depth respectively, for this purpose. I have found that this detent organization will securely hold the plug and receptacle bodies in assembled relation against even strong axial pulls tending to separate them, yet when it is desired to intentionally separate the plug and receptacle bodies 20, 22 this may be easily and quickly accomplished by employing an angular separating or breaking force which causes one particular portion of the bead 40 to leave the groove 42 before the remaining portions of the bead leave the groove.

To enable such relative angular movement to be employed, in accordance with the invention, the recesses 24 and the contactor sockets 25 of the receptacle body 22 are arranged to provide considerable clearance beyond the side edges of the contact prongs 26. This is clearly shown in FIG. 3, wherein the dotted lines in the recesses 24 represent the widths of the prongs 26. It will be seen that the prongs 26 can have appreciable angular movement while in the recesses 24 and sockets 25.

Also, the receptacle body 22 is provided with a pair of external, oppositely disposed flats 48 which will apprise a user of the proper direction in which to apply the relative angular movement. The flats 48 may have imprinted directions, such as the words press-bend to further inform the user as to required movement for effecting separation of the bodies 20, 22.

In accordance with the invention, there is provided a sealing element comprising an O-ring 50 at the base of the portion 38 of the receptacle body 22, for engagement with a cooperable sealing element in the form of a sharp annular shoulder 52 provided at the rim of the portion 36 of the body 20, said shoulder having a knife edge formation as clearly seen in FIG. 2. When the plug and receptacle bodies are assembled, the shoulder 52 will bite into the O-ring 50 with a force that is axial as distinguished from radial. This will result in an effective watertight seal between the bodies 20, 22 at the point or line of separation indicated at 54 in FIG. 1. The forces existing on the coupling parts due to the presence of the O-ring 50 tend to separate the bodies 20, 22 but such separation will not occur, nor can inadvertent or accidental separation occur inasmuch as most of these forces are in axial directions and are uniform. However, upon the user applying an angular or nonuniform force to the assembled bodies as mentioned above, their separation can readily occur, being now somewhat aided by the force exerted by the O-ring 50. A somewhat rounded shape of the snap bead 40 and groove 42 can result in a desirable detent action which facilitates the separation of the bodies upon the application of the proper breaking force. A particular shaping of the bead 40 also can facilitate the assembly of the bodies; and assembly also.is facilitated by the sloping surface 56 of the shoulder 52, cooperating with a slope or bevel 58 on the detent portion 38 of the body 22.

' Since radial pressures are not involved with the seal provided by the O-ring, any tendency for the ring to swell, or the presence of any dirt or foreign matter on the ring will not result in binding as the plug bodies are assembled or separated. The disposition of the ring 50 beyond the rim of the detent portion 36 of the body 20 also prevents any possibility of binding due to the ring swelling.

In accordance with the invention a seal is also provided where the cord 32 enters the collar 28 of the plug body 20. For this purpose, curved wedges 60 are arranged to be forced into the collar 28 between the inner walls thereof and the cord 32. A snap cap 62 having an internal groove 64 is pressed onto the collar 28 with the groove 64 occupied by an annular bead 66 of the collar. The cap 62 forces the wedges 60 tightly into sealing positions surrounding the cord 32. The wedges 60 also constitute an anchorage for the cord. A similar arrangement is utilized at the collar 30 of the receptacle body 22.

In circumstances where the receptacle portion is not being used it may be sealed by a snap cover, such a cover being illustrated in FIG. 8 and comprising a cup-shaped body 70 having a sharp sealing shoulder 72 for engagement with the O-ring 50, and having an annular or cylindrical detent portion 74 provided with an annular groove 76 to accommodate the detent bead 40 of the receptacle body 22. The seal and detent action of the cover 70 is similar to that already explained above in connection with the plug body 20.

FIG. 9 illustrates a receptacle part made in accordance with the invention, as mounted in an outlet box. In this figure the outlet box is indicated by the numeral 78, said box having a faceplate 80 of usual type. Within the box 78 is a receptacle comprising a body portion 82. The receptacle body 82 has a cylindrical detent portion 84 provided with an annular bead 86 for reception in the groove 42 of the plug body 20. An annular or sealing O-ring 88 is disposed at the base of the portion 84, for sealing engagement with the sharp shoulder 52 of the plug part. The sealing and detent action of the receptacle illustrated in FIG. 9 is similar to that already described above in connection with FIGS. l-7.

Another embodiment of the invention is illustrated in FIG. 10. The sealing and detent action in FIG. is similar to that already described above, except that the male and female telescoping detent portions are reversed, that is, the male telescoping portion is carried by the plug part 90 whereas the female telescoping portion is carried by the receptacle part 92. The plug 90 has an annular detent portion 94 provided with a detent bead 96 which is receivable in an annular groove 98 of a cylindrical or annular detent portion 100 of the receptacle part 92. A sealing O-ring 102 at the base of the portion 94 is engaged by a sharp annular shoulder 104 of the receptacle part 92, to effect the watertight seal. The contactor sockets 106 have an appreciable width, to provide clearance for the contact prongs 108 whereby relative angular or breaking movement of the plug and receptacle parts is possible, as explained above in connection with the sockets 24 and the embodiment of FIGS. 1-7. The assembly and disassembly of the receptacle and plug part of FIG. 10, and the sealing of said parts is similar to the action already described above, and accordingly these require no further detailed explanation.

It will now be understood from the foregoingthat I have provided novel and improved electrical plug and receptacle parts which are especially simple and economical to construct, and which provide not only a watertight sealing arrangement but also a simple and effective detent means by which the parts are securely locked together against accidental separation and yet may be easily and quickly separated and desired by a simple angular or breaking" movement. The plug and receptacle bodies may be readily economically molded of resilient plastic substance. The height of the detent bead and depth of the detent groove are not so great that the molded parts cannot be stripped from simple molds not provided with retractable slides. That is, the undercuts in the molds for forming the plug and receptacle parts are not so great that the molded bodies cannot be stripped from the molds without difficulty.'The location of the sealing O-ring, and the axial forces involved therewith are such as to provide an effective seal without interferring with the assembly or disassembly of the parts even though the O-ring should swell or become dirty. By properly selecting the relative diameters of the cylindrical detent portions of the bodies, and selecting the cooperable bead and groove dimensions the parts will assemble readily, will not come apart accidentally, and may be disassembled or separated easily and quickly from the proper breaking action. Important in this function is the short axial lengths of the portions 36, 38 and the close proximity of the detent shoulders to the front end surface 44 in the part 22, for example.

Variations and modifications are possible without departing from the spirit of the invention.

I claim:

1. An electrical coupling part comprising, in combination:

a. a body of insulating material, having a reference axis,

b. a pair of spaced-apart electrical contact members carried by said body and disposed substantially symmetrically with respect to the axis thereof, said members being accessible at one end of the body,

c. said body having an annular retainer portion located adjacent said members, said retainer portion being disposed concentrically with respect to the body axis and constituting the front end of the body,

d. said retainer portion being adapted to have a loose telescopic fit with a cooperable annular retainer portion of a companion part, and

e. an annular detent shoulder on said retainer portion, disposed closely adjacent the front edge thereof, and adapted to engage with a snap fit a cooperable shoulder on said cooperable retainer portion,

f. said annular retainer portion being tiltable with respect to the cooperable retainer portion of the companion part when attached thereto, thereby to effect a disengagement of its detent shoulder from the said cooperable detent shoulder,

g. said body having a sharp circular shoulder including a knife edge formation which is directed axially of the body and disposed forwardly of the annular detent shoulder thereof to enable it to bite into a cooperable, soft annular seal ring of a cooperable annular retainer portion.

2. A coupling part as in claim 1, wherein:

a. the annular retainer portion comprises a ring formation adapted to receive in it the said cooperable retainer por- U011.

3. A coupling part as in claim 1, and further including:

a. a cooperable part adapted to be applied to said body and having an annular retainer portion adapted for a telescopic fit with the retainer portion of said body, said cooperable part also having an annular detent shoulder on its retainer portion, engageable with the shoulder of said body retainer portion,

b. said retainer portions being tiltable with respect to each other when telescopically engaged, thereby to effect a disengagement of said detent shoulders to enable the cap to separate from the body, and

c. a resilient O-ring on said cooperable part, engageable by said knife edge formation of the sharp circular shoulder whereby the latter can bite into the O-ring.

4. A coupling part as in claim 1, wherein:

a. the body has a collar and an electric cord passing through the same,

b. a plurality of curved wedges in said collar, adapted to surround and press against the electric cord, and

c. a cap on said collar, engaged with said wedges to retain the latter in the collar and pressing against said cord.

5. A coupling part as in claim 4, wherein:

a. portions of the wedges fit inside each other.

6. A coupling part as in claim 1, and further including:

a. a cooperable coupling part comprising:

1 a body of insulating material, having a reference axis,

2. a pair of spaced-apart electrical contact members carried by said body and disposed substantially symmetrically with respect to the axis thereof, said members being accessible at one end of the body,

3. said body having an annular retainer portion located adjacent said members, said retainer portion being disposed concentrically with respect to the body axis and constituting the front end of the body,

4. said retainer portion being adapted to have a loose telescopic fit with the annular retainer portion of said firstmentioned coupling part,

5. an annular detent shoulder on the retainer portion of said cooperable coupling part, disposed closely adjacent the front edge thereof and adapted to engage said first-mentioned cooperable shoulder;

6. a resilient O-ring carried by said cooperable coupling part and engageable with the knife edge formation of said sharp circular shoulder,

7. said O-ring being disposed axially of the circular shoulder, and the latter biting into the O-ring.

7. A device as in claim 6, and further including:

a. cooperable plug and socket elements respectively on said bodies,

b. the body which has the socket elements further including recesses in which the socket elements are carried,

c. said recesses providing clearance around the plug elements to enable said tilting of the retainer portions to occur.

8. A device as in claim 6, wherein:

a. one retainer portion comprises a pluglike formation on which the O-ring is carried.

9. An electrical coupling part comprising, in combination:

a. a body of insulating material, having a reference axis,

b. a pair of spaced-apart electrical contact members carried by said body and disposed substantially symmetrically with respect to the axis thereof, said members being accessible at one end of the body,

0. said body having an annular retainer portion located adjacent said members, said retainer portion being disposed concentrically with respect to the body axis and constituting the front end of the body, d. said retainer portion being adapted to have a loose telescopic fit with a cooperable annular retainer portion of a companion part, and

e. an annular detent shoulder on said retainer portion, disposed closely adjacent the front edge thereof, and adapted to engage a cooperable shoulder on said cooperable retainer portion,

f. said annular retainer portion being tiltable with respect to the cooperable retainer portion of the companion part when attached thereto, thereby to effect a disengagement of its detent shoulder from the said cooperable detent shoulder,

g. said contact members comprising sockets adapted to receive standard flat prongs of a cooperable coupling part,

h. said body having recesses in which the sockets are disposed,

i. the dimensions of the recesses measured edgewise to said flat prongs being appreciably greater than the widths of the prongs, thereby to enable said tilting of the retainer portion with respect to an attached cooperable retainer portion having prongs disposed in said sockets. 

1. An electrical coupling part comprising, in combination: a. a body of insulating material, having a reference axis, b. a pair of spaced-apart electrical contact members carried by said body and disposed substantially symmetrically with respect to the axis thereof, said members being accessible at one end of the body, c. said body having an annular retainer portion located adjacent said members, said retainer portion being disposed concentrically with respect to the body axis and constituting the front end of the body, d. said retainer portion being adapted to have a loose telescopic fit with a cooperable annular retainer portion of a companion part, and e. an annular detent shoulder on said retainer portion, disposed closely adjacent the front edge thereof, and adapted to engage with a snap fit a cooperable shoulder on said cooperable retainer portion, f. said annular retainer portion being tiltable with respect to the cooperable retainer portion of the companion part when attached thereto, thereby to effect a disengagement of its detent shoulder from the said cooperable detent shoulder, g. said body having a sharp circular shoulder including a knife edge formation which is directed axially of the body and disposed forwardly of the annular detent shoulder thereof to enable it to bite into a cooperable, soft annular seal ring of a cooperable annular retainer portion.
 2. A coupling part as in claim 1, wherein: a. the annular retainer portion comprises a ring formation adapted to receive in it the said cooperable retainer portion.
 2. a pair of spaced-apart electrical contact members carried by said body and disposed substantially symmetrically with respect to the axis thereof, said members being accessible at one end of the body,
 3. said body having an annular retainer portion located adjacent said members, said retainer portion being disposed concentrically with respect to the body axis and constituting the front end of the body,
 3. A coupling part as in claim 1, and further including: a. a cooperable part adapted to be applied to said body and having an annular retainer portion adapted for a telescopic fit with the retainer portion of said body, said cooperable part also having an annular detent shoulder on its retainer portion, engageable with the shoulder of said body retainer portion, b. said retainer portions being tiltable with respect to each other when telescopically engaged, thereby to effect a disengagement of said detent shoulders to enable the cap to separate from the body, and c. a resilient O-ring on said cooperable part, engageable by said knife edge formation of the sharp circular shoulder whereby the latter can bite into the O-ring.
 4. said retainer portion being adapted to have a loose telescopic fit with the annular retainer portion of said first-mentioned coupling part,
 4. A coupling part as in claim 1, wherein: a. the body has a collar and an electric cord passing through the same, b. a plurality of curved wedges in said collar, adapted to surround and press against the electric cord, and c. a cap on said collar, engaged with said wedges to retain the latter in the collar and pressing against said cord.
 5. A coupling part as in claim 4, wherein: a. portions of the wedges fit inside each other.
 5. an annular detent shoulder on the retainer portion of said cooperable coupling part, disposed closely adjacent the front edge thereof and adapted to engage said first-mentioned cooperable shoulder;
 6. a resilient O-ring carried by said cooperable coupling part and engageable with the knife edge formation of said sharp circular shoulder,
 6. A coupling part as in claim 1, and further including: a. a cooperable coupling part comprising:
 7. A device as in claim 6, and further including: a. cooperable plug and socket elements respectively on said bodies, b. the body which has the socket elements further including recesses in which the socket elements are carried, c. said recesses providing clearance around the plug elements to enable said tilting of the retainer portions to occur.
 7. said O-ring being disposed axially of the circular shoulder, and the latter biting into the O-ring.
 8. A device as in claim 6, wherein: a. one retainer portion comprises a pluglike formation on which the O-ring is carried.
 9. An electrical coupling part comprising, in combination: a. a body of insulating material, having a reference axis, b. a pair of spaced-apart electrical contact members carried by said body and disposed substantially symmetrically with respect to the axis thereof, said members being accessible at one end of the body, c. said body having an annular retainer portion located adjacent said members, said retainer portion being disposed concentrically with respect to the body axis and constituting the front end of the body, d. said retainer portion being adapted to have a loose telescopic fit with a cooperable annular retainer portion of a companion part, and e. an annular detent shoulder on said retainer portion, disposed closely adjacent the front edge thereof, and adapted to engage a cooperable shoulder on said cooperable retainer portion, f. said annular retainer portion being tiltable with respect to the cooperable retainer portion of the companion part when attached thereto, thereby to effect a disengagement of its detent shoulder from the said cooperable detent shoulder, g. said contact members comprising sockets adapted to receive standard flat prongs of a cooperable coupling part, h. said body having recesses in which the sockets are disposed, i. the dimensions of the recesses measured edgewise to said flat prongs being appreciably greater than the widths of the prongs, thereby to enable said tilting of the retainer portion with respect to an attached cooperable retainer portion having prongs disposed in said sockets. 